A polyamide typically represented by nylon 6 and nylon 66 is excellent in moldability, mechanical properties and chemical resistance, and widely used as a material for various parts of automobiles, industrial materials, clothing, and electric, electronic or industrial applications.
A polyamide is frequently used particularly as automotive parts such as parts related to a basic engine, e.g., engine covers, connectors to be directly connected to the cover, and air intake manifolds, relay boxes, gears, and clips.
In recent years, resulting from the downsizing of an engine compartment of automobiles and enhancing the performance or power output of an engine, the temperature in the engine compartment and the temperature of engine cooling water tend to increase. Accordingly, a resin product for use is required to have further higher heat resistance. In other words, a polyamide having excellent heat resistance even higher than nylon 66 is required.
Further, replacement of metal parts with resins is underway, so that resin materials are required to have higher rigidity and impact resistance (e.g., toughness) than ever. Furthermore, the resin parts are required to have excellent joint (welding) properties to each other. The requirements for the parts constituting an engine or a motor (including battery materials), in particular, are increasing in combination with needs for improvement in fuel efficiency through weight saving.
Herein, various studies have been conducted on, as a material for replacing metal, semi-aromatic polyamides including nylon 6T, which have excellent heat resistance and high rigidity (PTL 1).